This disclosure relates generally to the field of multimedia data. More particularly, but not by way of limitation, it relates to a technique for modifying media files to incorporate additional or replacement content without modification of the original media file.
Media content is currently distributed as a file composed of a header portion and a data portion. FIG. 1 illustrates a typical media file 100. Tables 110 within the header portion identify (point to) content 120 (e.g., tracks). The media file, as originally created and then downloaded by a user, has typically been gone through a quality control process that has certified the content in the media file. Incorporating new content therefore incurs the cost of re-qualifying the modified media file, which requires the recoding and/or re-downloading of the entire media file with the new data incorporated therein. Typically requalification of a media file grows exponentially with each element added to the media file, because each combination of modules that could be selected for playing the media file should be qualified.
In addition, this format may not provide the ability to easily incorporate new content once the file has been created and/or downloaded (e.g., a secondary subtitle or audio track). In some implementations, the media file structure may allow for incorporating additional content, but the media file 100 may not be writable when the additional content is to be incorporated. In other implementations, the media file structure may not allow content files to be dynamically grown, thus the desired new information may not just be inserted into the media file.
Because the monolithic media file contains all of the original content and all additional content, the time required to download the content by a user and the amount of storage needed to store the downloaded media file increases as new content is added, even if a particular user has no interest in all of the additional content. For example, an original media file may have content only in English, but as subtitles or dubbing tracks are added to translate the original media into other languages, a person desiring only the English version or just one other language additional content must download the entire monolithic file with every available language.